1. Field of the Invention
The present invention relates to a data copying system and a date copying method for providing a copyright protection function, as well as a reading apparatus, a writing apparatus, and a recording medium for use in such a data copying system.
2. Description of the Related Art
Methods for encrypting information recorded on a recording medium for providing a copyright protection function are known in the art. For example, unauthorized decryption of encrypted information can be made substantially difficult by adopting a hierarchical structure for encryption keys that are used for the encryption of the information. Such techniques are intended for preventing unauthorized copying of information which is recorded on the recording medium.
The standards which are proposed for DVD-Audio, a prospective next-generation audio medium, require that an enhanced copyright protection function be provided. The requirement includes the prohibition of a xe2x80x9cthird generation digital copyxe2x80x9d from a ROM (read only memory) disk.
As used herein, the prohibition of a xe2x80x9cthird generation digital copyxe2x80x9d means that, whilst a ROM disk (i.e., a xe2x80x9cfirst generation copyxe2x80x9d) may be allowed to be duplicated or copied once onto a RAM disk (random access memory disk) (i:e., xe2x80x9ca second generation copyxe2x80x9d), any further copying of that RAM disk to another RAM disk (which would result in xe2x80x9ca third generation copyxe2x80x9d) in prohibited.
According to the present invention, there is provided a copying system for copying information recorded on a first recording medium onto a second recording medium wherein the first recording medium is recorded with copying control information for representing conditions for permitting copying of the information recorded on the first recording medium, the copying control information being multiplexed within the information recorded on the first recording medium, wherein the copying system includes: a reading section for reading the information from the first recording medium; a detection section for detecting the copying control information within the information read from the first recording medium, a modification section for, if the copying control information represents a condition that xe2x80x9conly copying to a second generation copy is permittedxe2x80x9d, modifying the copying control information so as to prohibit any further copying, and a writing section for writing information including the modified copying control information, onto the second recording medium.
In one embodiment of the invention, the copying control information is represented by a combination of two kinds of watermarks.
In another embodiment of the invention, the information recorded on the first recording medium includes a plurality of frames, the copying control information being multiplexed within a predetermined number of frames among the plurality of frames.
In another aspect of the invention, there is provided a copying method for copying information recorded on a first recording medium onto a second recording medium, wherein the first recording medium is recorded with copying control information for representing conditions for permitting copying of the information recorded on the first recording medium, the copying control information being multiplexed within the information recorded on the first recording medium, wherein the copying method includes the steps of: reading the information from the first recording medium; detecting the copying control information within the information read from the first recording medium; if the copying control information represents a condition that xe2x80x9conly copying to a second generation copy is permittedxe2x80x9d, modifying the copying control information so as to prohibit any further copying; and writing information including the modified copying control information, onto the second recording medium.
In another aspect of the invention, there is provided a reading apparatus for reading information recorded on a first recording medium, wherein the first recording medium is recorded with copying control information for representing conditions for permitting copying of the information recorded on the first recording medium, the copying control information being multiplexed within the information recorded on the first recording medium, and wherein the reading apparatus is connected via a bus to a writing apparatus for writing the information onto a second recording medium, the reading apparatus including: a reading section for reading the information from the first recording medium; a detection section for detecting the copying control information within the information read from the first recording medium; and a control section for, if the copying control information represents a condition that xe2x80x9ccopying Is entirely prohibitedxe2x80x9d, prohibiting the information from being output to the bus.
In another aspect of the invention, there is provided a writing apparatus connected via a bus to a reading apparatus for reading information recorded on a first recording medium, the writing apparatus including: a detection section for receiving the information output from the reading apparatus via the bus and detecting copying control information within the received information read; a modification section for, if the detected copying control information represents a condition that xe2x80x9conly copying to a second generation copy is permittedxe2x80x9d, modifying the copying control information so as to prohibit any further copying; and a writing section for writing information including the modified copying control information, onto a second recording medium.
In another aspect of the invention, there is provided a recording medium recorded with information representing a content to be recorded, and copying control information representing a condition for permitting copying of the information recorded on the recording medium, wherein the copying control information is multiplexed within the information recorded on the recording medium.
In one embodiment of the invention, the copying control information is represented by a combination of two kinds of watermarks.
In another embodiment of the invention, the information recorded on the first recording medium includes a plurality of frames, the copying control information being multiplexed within a predetermined number of frames among the plurality of frames.
In still another embodiment of the invention, the copying control information selectively represents one of at least three conditions: xe2x80x9ccopying is permitted over an unlimited number of generationsxe2x80x9d; xe2x80x9conly copying to a second generation copy is permittedxe2x80x9d; or xe2x80x9ccopying is entirely prohibitedxe2x80x9d.
Thus, the invention described herein makes possible the advantages of (1) providing a data copying system and a data copying method which permit the copying of a first generation copy (e.g., a ROM disk) into a second generation copy (e.g., a RAM disk) in compliance with the DVD-Audio standards; and (2) providing a reading apparatus, a writing apparatus, and a recording medium for use in such a data copying system.
These and other advantages of the present invention will become apparent to those skilled in the art upon reading and understanding the following detailed description with reference to the accompanying figures.